A method for the determination of dixanthogens

One mole of diethyl dixanthogen reacts with 26 moles of chloramine-T, and this reaction can be used for the determination of the dixanthogen. Higher alkyl dixanthogens react in a more complicated fashion, but may still be estimated using an empirical correction.

A weighted mean square method of linearization in non-linear oscillations

The paper deals with a linearization technique in non-linear oscillations for systems which are governed by second-order non-linear ordinary differential equations. The method is based on approximation of the non-linear function by a linear function such that the error is least in the weighted mean square sense. The method has been applied to cubic, sine, hyperbolic sine, and odd polynomial types of non-linearities and the results obtained are more accurate than those given by existing linearization methods.

Model For Regulation Of Delta-Aminolevulinate Synthetase Induction In Rat-Liver

A reciprocal relationship exists between the cytochrome P-450 content and d-aminolaevulinate synthetase activity in adult rats. In young rats the basal d-aminolaevulinate synthetase activity is higher and the cytochrome P-450 content is lower compared with the adult rat liver. Administration of allylisopropylacetamide neither induces the enzyme nor causes degradation of cytochrome P-450 in the young rat liver, unlike adult rat liver. Allylisopropylacetamide fails to induce d-aminolaevulinate synthetase in adrenalectomized–ovariectomized animals or intact animals pretreated with successive doses of the drug, in the absence of cortisol. The cortisol-mediated induction of the enzyme is sensitive to actinomycin D. Allylisopropylacetamide administration degrades microsomal haem but not nuclear haem. Haem does not counteract the decrease in cytochrome P-450 content caused by allylisopropylacetamide administration, but there is evidence for the formation of drug-resistant protein-bound haem in liver microsomal material under these conditions. Phenobarbital induces d-aminolaevulinate synthetase under conditions when there is no breakdown of cytochrome P-450. On the basis of these results and those already published, a model is proposed for the regulation of d-aminolaevulinate synthetase induction in rat liver.

Studies on induction of delta-aminolevulinic acid synthetase in mouse liver

Administration of 3,5-diethoxy carbonyl-1,4-dihydrocollidine (DDC) to mice resulted in a striking increase in the level of δ-aminolevulinic acid (ALA) synthetase in liver. Although the enzyme activity was primarily localized in mitochondria and postmicrosomal supernatant fluid, a significant level of activity was also detected in purified nuclei. The time course of induction showed a close parallelism between the bound and free enzyme activities with the former always accounting for a higher percentage of the total activity as compared to the latter. Studies with cycloheximide indicated a half-life of around 3 hr for both the bound and free ALA synthetase. Actinomycin D and hemin prevented enzyme induction when administered along with DDC, but when administered 12 hr after DDC treatment Actinomycin D did not lead to a decay of either the bound or free enzyme activity and hemin inhibited the bound enzyme activity but not the free enzyme level. The molecular sizes of the mitochondrial and cytosolic ALA synthetase(s) were found to be similar on sephadex columns.

Crystallographic Evolution, Dielectric, and Piezoelectric Properties of Bi4Ti3O12:W/Cr Ceramics

W/Cr codoped Bi4Ti3O12 ceramics, Bi4Ti3-xWxO12+x+0.2 wt%Cr2O3 (BITWC, x=0-0.15), were prepared using a solid-state reaction method. The crystallographic evolution and phase analysis were distinctly determined focusing on the X-ray diffraction peak changes in (020)/(200) and (220)/(1115) diffraction planes, by which the lattice parameters, a, b, and c can be refined. The thermal variations of permittivity, dielectric loss (tan delta), impedance, and electrical conductivity properties were characterized. A decrease in the values of Curie temperature from 675 degrees to 640 degrees C and an increase in the values of the dielectric constant due to an increase of W6+/Cr3+ content were observed. The highest piezoelectric constant, d(33) of 22 pC/N, was achieved with the composition of Bi4Ti2.975W0.025O12.025+0.2 wt% Cr2O3. Also, this composition had a lower electrical conductivity than the other investigated compositions.

Pt2+ Dispersed in Ce0.83Ti0.15O2-delta: Significant Improvement in PROX Activity by Ti Substitution in CeO2 in Hydrogen Rich Stream

Pt2+ ion dispersed in CeO2, Ce1-xTixO2-delta and TiO2 have been tested for preferential oxidation of carbon monoxide (PROX) in hydrogen rich stream. It is found that Pt2+ substituted CeO2 and Ce(1-x)TixO(2-delta) in the form of solid solution Ce0.98Pt0.02O2-delta and Ce0.83Ti0.15Pt0.02O2-delta are highly CO selective low temperature PROX catalysts in hydrogen rich stream. Just 15% of Ti substitution in CeO2 improves the overall PROX activity.

A new method of producing local enhancement of buoyancy in liquid flows

We describe here a novel method of generating large volumetric heating in a liquid. The method uses the principle of ohmic heating of the liquid, rendered electrically conducting by suitable additives if necessary. Electrolysis is prevented by the use of high frequency alternating voltage and chemically treated electrodes. The technique is demonstrated by producing substantial heating in an initially neutral jet of water. Simple flow visualisation studies, made by adding dye to the jet, show marked changes in the growth and development of the jet with heat addition.

Studies on non-specific interference due to serum in the avidin-biotin microELISA for monkey chorionic gonadotropin and a method for its elimination

A study has been carried out on the non-specific interference due to serum in the avidin biotin micro-ELISA for monkey chorionic gonadotropin. Results suggest that it is not due to any proteolytic activity in the serum, but immunoglobulin or associated factors interfering at the level of antigen-antibody interaction. This interference was eliminated by heating samples at 60°C for 30 min.